104 



Kew Jersey growers at Yineland destroy the grape-vine leaf-hopperSy 

 by tarring botli sides of a stiff card-board about 15 by 20 inches nailed 

 to a wooden handle of some kind. The grower walks between the 

 rows, stirring the vines so as to induce the specimens to fly, and 

 waving the tarred boards forward and backward most of the specimens 

 are captured. More are captured on the back of the board than are 

 taken on the front of it. Two or three journeys through the vineyard 

 are usually sufficient to clear it of insects. 



Mr. Eiley stated that there could be no doubt as to the dual nature 

 of honeydew, or rather of its treble nature, as he had long been satis- 

 fied of the facts from his own observation. The liquid thrown off' by 

 the honey tubes is frequently ejected to a considerable distance and 

 show^ered in the form of a fine dew upon the foliage beneath, and this 

 is the explanation of the very general glossiness of the leaves of trees 

 affected by certain species of Aphides, especially in early summer. 

 That the excrement is also liquid and saccharine may be easily proved 

 by observation not only in this family, but in the Coccidse, while there 

 is a third kind of honey dew which has no connection with insect 

 secretion, but is an extravasation of the sap of plants caused particu- 

 larly by great extremes of temperature during rapid growth. 



THE PEAR-LEAF BLISTER MITE. 



( Phy top t us pyri . ) 

 By M. V. Slingerland, Ithaca, X. Y. 



This pest is alarmingly on the increase in the United States and 

 Canada, and threatens very serious injury to our pear interests unless 

 speedily checked. The mite was discussed at some length in Bulletin 

 23 of the Cornell Experiment Station. Since then I have made a few 

 additional observations and have discovered what I believe will prove 

 a practicable method of exterminating the pest. 



The life-history of the mite appears to be, in brief, as follows : The 

 mites which are hardly visible to the unaided eye api3ear on the leaves 

 as they are unfolding in the spring and form small bright red spots or 

 blisters, having small openings on the lower side of the leaf 5 the eggs 

 are laid within the galls and the young escape through the opening 

 and form new galls. As the season advances the galls change color, 

 and about June 1 they are green, distinguishable fi'om the remainder 

 of the leaf only by their slightly raised corky appearance. In about a 

 week they assume the characteristic black or brown color which they 

 retain until the leaves fall in autumn. When very numerous, the galls 

 coalesce and often cover nearly the whole leaf. In the autumn, before 

 the leaves fall, the mites leave the galls and enter the winter buds. 

 Usually they are to be found beneath the two or three outer scales of 



